Storage tank for volatilizable material



May 26, 1959 F. 'FFFQLTZ ETIAL STORAGE TANK FOR VOLATILIZABLE MATERIAL Filed Dec. 14, 1955 FIG? L w; 2 y 0 4 4 w M Q A 8 Will! 1 J lllllllllXL/lllll H Al |lll| :..L| l|l|||l||l|| yVllll frederic y' l Eugene M. Seize/(om United States Patent STORAGE TANK FOR VOLATILIZABLE MATERIAL Frederick F. Foltz, Hammond, Ind., and Eugene M. Setzekorn, Elmhurst, Ill., nssignors to US. Industries, Inc., New York, N.Y., a corporation of Delaware Application December 14, 1955, Serial No; 553,077

11 Claims. (Cl. 48-176) This invention relates to a unit of conservation equipment in the form of a tank for the storage of gaseous materials or volatile liquids.

The term conservation equipment is derived from the fact that the tank embodies means for adjustment of its volumetric capacity automatically to accommodate an increase in the volume of vapors or gases which are formed within the tank during the hotter portions of the .day and the lesser volume of vapors or gases present in the tank during the colder portions of the evening, thereby to retain the gaseous materials or vapors which are formed during the heat of the day for recovery by condensation and without the loss occasioned with other types of storage equipment where it is necessary to vent or bleed off the vapors to prevent increase in pressures beyond a predetermined level. In large storage tanks of the type forming the subject matter of this invention, the loss of vapors or gases would be extensive if vented into the atmosphere to prevent the buildup of pressures beyond dangerous levels. Thus it is desirable to provide a tank of the type described in which the volumetric capacity of the container can be automatically adjusted to accommodate the normal contractions and expansions of liquids and gases contained therein and the vaporization and condensation of liquids contained therein, generally referred to in the art as breathing, with out noticeable loss of the materials.

It is an object of this invention to produce a tank of the type described for conservation of the gases and vapors therein during normal breathing cycles.

More specifically, it is an object of this invention to provide a tank of the type described having a roof or cover mounted for endwise movement in the vertical direc tion relative the tank shell to increase or decrease the space available in the tank for the storage of liquids, vapors, gases or other volatilizable content material; which embodies means for guiding the roof in its vertical move ment to minimize distortions or angularity in the position of the roof which might otherwise interfere with the operation or movement thereof; which embodies means also to prevent undesirable rotational movement of the roof relative the tank shell which would otherwise cause improper alignment and interfere with the movement of the parts in operation; which embodies means constantly urging the roof to return to normal position thereby properly to align the roof for operation in the manner intended, and in which the means are provided for support of the roof, at least in part, by the side walls of the tank shell all around properly to align the roof in its deflated position and prevent distortions thereof while in position of rest and to take some of the load off the roof from the central support thereby to improve the strength and stability of the structure; which embodies means in the construction of the roof to minimize the distortion or destruction of parts in operation and to prevent separation under loads normally existing in the apparatus thereby to increase the life and utility of the unit and reduce the cost and upkeep thereof, and which is sturdy in construction and eificient in operation and which is formed of parts which can be efliciently and economically assembled into a tank having additional improvement over and above those previously described.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, embodiments of the invention are shown in the accompanying drawing in which Figure l is a schematic sectional elevational view of a conservation tank embodying the features of this invention; Figure 2 is a sectional elevational view of a corner portion of the tank assembly shown in Figure 1; Figure 3 is a sectional elevational view of a section of the tank-shown in Figure 2 with a modification in the means for urging the cover into proper alignment; Figure 4 is a sectional view taken along the line 44 of Figure 2; and Figure 5 is a sectional view similar to that of Figure 4 for showing a further modification in the structure of the tank.

Referring now to the drawing, the tank, indicated generally by the numeral 10, is an open-type tank having cylindrical side walls 12, a base 14 which rests upon the earth or other suitable support and which is joined to the lower edge of the side walls 12 all around in sealing relation to close the bottom end of the tank, and a structure for supporting the roof, indicated generally by the numeral 16, in a manner which more uniformly distributes the load over the tank thereby to prevent distortions and deteriorations in use and which operates also to maintain proper alignment of the parts in operation, thereby to minimize interferences in use of the equipment.

The improved support comprises the usual center post 18 but instead of providing a cap or platform on the upper end for receiving the roof in position of rest, when in the deflated position, the-upper end portion of the tank is provided with a plurality of rafters 20 in the form of elongate structural metal members which extend outwardly radially in equally, circumferentially spaced apart relation from the center post 18. The inner end portions of the metal members 20 are secured, as by welding or riveting, to the center post 18 while the outer end portions of the metal members, illustrated as H beams,

terminate a short distance inwardly from the upper end of the side walls 12 of the tank shell and are secured, as by rivets 22. or by welding, to an upwardly extending flange 24 on the inner end portion of rafter clips 26, each of which is in the form of a metal plate fixed, as by welding, riveting or the like, to the side walls 12 of the tank shell in the upper end portion thereof, but spaced a short distance below their upper edge 28.

Thus the center post 18 and the tank shell are joined one with the other by the stiff radial beams 20 and the bottom wall 14 of the tank, thereby to provide an integral unit which operates to hold and reinforce the side walls of the tank in their desired relation and to prevent collapse while also providing support for the roof in a manner which distributes the loads between the roof and betweeen the center posts and tank shell to avoid the concentration of forces which might otherwise cause distortions, and which assembly also embodies means for aligning the roof with the tank when at rest on the rafters and on the side walls of the tank, as will hereinafter be described, in the deflated position. For this purpose, the rafters or beams 20 are arranged at an incline from the center post 18 outwardly to the clip 26 in which the incline is adapted to correspond to the contour of the underside of the roof 16 in the same area so as to engage the underside of the roof radially throughout in spaced apart sections when the roof is in the deflated position, while also engaging the roof circumferentially all around the outer edge portion on the upper edge of the tank shell, as will hereinafter be described. I

The cylindrical walls 12 of the tank shell are further strengthened and reinforced by one or more inwardly directed annular shell girders 30 and 32 fixed at their outer edges to vertically spaced apart portions of the side walls of the tank while the upper end portion of the tank is still further reinforced by a metal ring member 3d fixed, as by welding, to the upper edge 28 of the tank shell to provide a portion extending inwardly thereof a short distance in the form of a horizontally disposed annular fiange upon which a portion of the roof is adapted to rest when in the deflated positon, thereby to support the roof all around in a manner which properly aligns the roof in position of rest and uniformly distributes the load therebetween. In this manner, the concentration of loads is further minimized more ably to support the roof without such stresses or strains on limited areas of. the roof or tank shell as might otherwise cause distortion or deterioration. Each of the girders 3d and 32 is further equipped with flanged plates 36 and 38 respectively which extend upwardly, as in Figure l, or downwardly as in Figure 2, from the outer edges of the girders to stiffen and reinforce the girders and thereby materially to in crease the strength of the side wall construction of the tank shell.

The usual launder it is provided about the upper end portion of the tank shell, including the launder shell in the form of a cylindrical housing 42 of larger diameter than the tank shell, on rings arranged concentrically about the upper end portion thereof to provide an annu lar space 44 therebetween which is open at the upper end and closed at the lower end by a base plate 46 in the form of an annular ring secured at its inner edge to the outer side walls of the tank shell, and to which the lower edge of the housing 42 is secured to provide fluidtight seals therebetween. The launder space is filled with a suitable liquid 48, such as water, oil or the like. The launder shell is further reinforced and stiffened by a launder girder h fixed to extend outwardly from the upper end portion thereof spaced a short distance from the upper edge. The launder terminates a short distance below the level of the flange 34 upon which the roof comes to rest in deflated position, so that the roof will rest its weight on the beams 24 and the tank shell 12, as distinguished from the launder 40.

The roof 16 comprises a metal member of conical shape having its apex S2 in the center substantially in endwise alignment with the center post supper-"1g the rafters and sloping downwardly from the apex at n angle corresponding to the slope of the beams 26. An

important improvement in the tank structure resides in the construction of the end portion of the roof wherein the longitudinally disposed arm usually joined at its inne end to the outer end portion of the roof for support of the skirt, which depends downwardly therefrom into the launder, is instead positioned beneath the end portion of the roof with the inner end portion 54 of the horizontally disposed arm 56, in the form of an annular ring member, extending inwardly beyond the end portion 58 of the roof. Thus the end portion of the roof is joined to the horizontally disposed arm 56 intermediate the lateral edges of the arm and preferably at about the center portion thereof, while the inner end portion 54 of the arm is spaced downwardly a short distance below the corresponding portion of the roof and is joined thereto to provide a rigid structure by an annular ring 69 which is secured, as by welding, at its upper edge to the underside of the roof and is similarly secured, as by welding, to the inner edge of the arm 56. A portion of the ring 60 extends downwardly below the arm further to stiffen and strengthen the roof girder construction described.

By this arrangement, a triangular girder section is provided for the roof in which the roof itself forms an integral part as in the area between the ring 66' and the end portion of the roof which is joined to the arm 56 so that forces operating are received in the portion of the arm spaced inwardly from the end portion of the roof, thereby more uniformly and more widely to distribute the load and prevent distortions. In addition, any such forces operating on the inner portion of the arm, which includes substantially all of the forces capable of being developed, are effective only in their vertical components which tends to pivot the arm 56 about the end portion of the roof as a pivot, which force is further resisted by the vertical leg 60 of the triangular girder which engages the underside of the roof. Thus there is required to be a force which would be much greater than the forces which have heretofore been required to cause separation between the horizontally disposed arm 56 and the roof in previous constructions. For example, when in deflated position, the portion of the horizontally disposed arm spaced inwardly from the end of the roof comes to rest on the horizontally disposed flange 34 joined to the upper edge of the tank shell, thereby to provide engagement between the aligned surfaces over substantial areas thereof which is effective not only properly to align the elements at rest but also to transfer the load over a substantial area inwardly of the edge of the roof.

The triangular construction of the roof girder is not only effective more widely and more uniformly to spread the forces, but it also prevents concentration of forces or the development of binding forces during operation. A cylindrical skirt 62 depends from an intermediate portion of the horizontally disposed arm 56 into the launder 40 for immersion of the end portion of the skirt in the liquid 4?) for effecting the desired sealing relationship which confines the vapors and gases within the tank while permitting movement of the roof in the vertical direction from deflated to an extended position during normal breathing of the tank. Thus vapors are unable to escape from the tank and it becomes unnecessary to vent any of the vapors from the tank to prevent the build-up of excessive pressures during the heat of the day or during filling of the tank. The horizontally disposed arm 56 extends outwardly below the launder 40 as a rain shield to protect the underlying portions of the tank structure.

A further concept of this invention resides in the means for preventing tilting or turning movement of the roof relative the tank shell responsive to winds or other forces whereby interferences might be developed with the proper operation of the device during increase or decrease in the volumetric capacity of the tank, thereby to avoid the development of dangerous conditions in the storage of gases or liquids. In accordance with the practice of this invention, the roof assembly is guided in its vertical movements and is restricted in its relative rotational movements by means of posts 64 which are joined at their upper ends to the arms 56 of the roof girders in an area between the ring members 60 and the portion of the arm adapted to be engaged by the flange 34 when in deflated position. A plurality of such posts in equally spaced apart relation about the tank depend from the roof girders vertically downwardly through aligned open- 'ings 66 and 68 in the vertically spaced, horizontally disposed shell girders 30 and 32 respectively.

As illustrated in greater detail in Figures 2 and 4, the posts 64, equally spaced about the peripheral portion of the roof and spaced inwardly a short distance from the inner wall 12 of the tank shell to extend through the aligned openings 66 and 68 in the girder plates, are preferably formed in cross-section as H or I beams. Instead, as illustrated in Figure 5, the posts may be formed of rectangular sections or else they may be formed of curvilinear sections and the like.

As illustrated in Figures 2 and 4, the means for centering the posts within the respective openings comprises roller bearings 70 mounted for free rotational movement within holders 72 which are shiftable endwise within tubular housings 74 between an extended position defined by stops in the housing and a retracted position. In the extended position, the rollers are adapted to project a substantial distance toward the opening of the girder to engage the adjacent wall of the post extending therethrough even when the post is disposed in the opposite portion of the opening. The posts are constantly urged to center within the opening by coil springs 76 which are confined within the housings 74 with one end bearing against the base 78 of the housing while the other end bears against the holder constantly to urge the roller bearing, 72 into contacting relation with the adjacent wall of the post. At least one such housing is secured to the wall of the girder to face inwardly in the radial direction and outwardly in the radial direction to engage the opposite radial walls 80 and 82 respectively of the post extending downwardly through the respective opening and at least one such housing is mounted on the girder to face laterally in one circumferential direction and laterally in the opposite circumferential direction to engage the opposite circumferential walls 84 and 86 respectively of the post thereby to retain the post substantially centered within the respective openings.

Usage of a pair of girders as illustrated by the numerals 30 and 32 for resilient engagement with the posts enhances the stability of the structure and the ability to maintain the posts in the desired centered relationship to control the movements of the roof. When a pair of such centering members in vertically spaced apart relation are employed, it is preferred to locate the upper girder and centering units as close to the top of the tank shell as possible more ably to provide the desired guiding relation. The other or others of the centering members and girders can be located downwardly thereof but with the lowermost units spaced from the end of the post, when the roof is in the deflated position, by an amount greater than the length of the skirt immersed in the fluid of the launder and by an amount which is at least as great as the rise permitted to take place in the roof from its deflated position. This spaced relationship determines the expansibility or rise of the tank.

Instead of making use of roller bearings of the type described, use may be made of rollers 90 rigidly mounted on circumferentially aligned and radially aligned axes for engagement with the walls of the posts in position of use constantly to engage the radial and circumferential walls of the posts from opposite directions to permit free endwise movement with limited radial and circumferential movements. Thus the posts are rigidly held in vertical alignment to maintain the roof assembly in its centered and aligned relationship regardless of the forces operating to cause angularity or circumferential displacement.

It is preferred, however, to make use of resilient engagement with the portions of the post adjacent the opening as illustrated in connection with the roller bearing assemblies. By way of a preferred modification in which use is made of rollers 92, as illustrated in Figure 3, the rollers 92 are mounted for rotational movement upon shafts 94 journalled in the outer end portions of arms 96 which are pivoted intermediate their ends on pins 98 extending axially from a bracket 100 fixed to the girder 30 or 32 in the desired spaced relation with the walls of the post. A coil spring 102, located between a stop 104 and the end portion 106 of the arm 96 beyond the pivot, constantly urges the arm to rock about its pivot in a direction to bring the roller 92 into resilient engagement with the adjacent wall of the post 64. As in the structure previously described, pairs of such units are mounted on the girders about each opening for engaging the posts in opposed radial and circumferential directions.

Instead of roller hearings or rollers of the type described, use may be made of leaf springs (not shown) secured to the underside or top side of the girders 30 and 32 and having curvilinear end portions extending into the path of the posts extending downwardly through the openings resiliently to engage the adjacent walls of the post in the opposite radial and circumferential directions to edge the posts into a common area therebetween in the opening to center the posts while permitting limited flexibility, as in the other resilient systems, for slight shifting of the posts radially or circumferentially within the limitations imposed by the openings.

Angularity and relative circumferential movement of the posts and the connected roof can be further resisted by such means, as illustrated in greater detail in Figures 2 and 3, wherein use is made of a track 110 radially aligned with each post 64 and fixed in vertical alignment with the posts to the inner wall 12 of the tank shell. Each post 64 is provided at its lower end portion with means extending outwardly radially from the post into engagement with the track to permit guided vertical movement of the post and roof but to resist relative radial movement and relative circumferential movement.

In the modification shown in Figure 2, the means supported by the post in operative engagement with the track comprises a ball bearing 112 mounted for free rotational movement in a holder 114 radially slidable within a housing 116 secured at its inner end to the outer wall of the post 86. The holder and ball bearing are urged outwardly toward the extended position of adjustment into resilient engagement with the track by means of a spring 118 confined within the housing and having one end bearing against the base of the housing while the other end bears against the rear wall of the holder.

In Figure 3, the means mounted on the post for operative engagement with the track is illustrated as a roller 120 mounted for rotational movement upon a shaft 122 journalled in the outer end portion of an arm 124 which is pivoted intermediate its ends on a pin 126 extending circumferentially from a bracket 128 fixed to the outer radial wall of the post. The roller is constantly urged into resilient engagement with the track by means of a spring 130 having one end bearing against a stop 132 on the bracket while the other end bears against the arm 134 integral with the arm 124 and extending beyond the pivot pin 126. It will be understood that other means can be employed for operative engagement between the post and the track.

In operation, when the tank is empty or else when the vapors within the tank have been condensed, as during the cool of the night, the roof will be in the deflated position with the arm 56 at rest on the flange 34 at the upper end of the tank shell and with the sloping roof resting upon the top side of the radially extending girders or beams 20 whereby the roof is supported all around its outer periphery on the tank shell and also supported radially throughout its length in spaced apart portions on the beams with the result that very little, if any, concentration of forces exists in the structure, when in the deflated position, and the roof is held in the desired alignment for operation. When in the deflated position, the

skirt 62 extends downwardly into the fluid 48 of the launder to its maximum distance and the posts 64 extend downwardly below the lowermost girder 32 by an amount greater than the rise which is capable of taking place.

As additional material is introduced in the tank or as vapors are formed with rising temperature, the pressures built up within the tank are suflicient to urge the roof to rise vertically relative the tank shell so that the increased volume of material can be accommodated within the tank without exceeding such pressures as are necessary to overcome the weight of the roof and its supported structure. The roof is guided in its rising and lowering movements by the means described which resiliently engage the posts depending from the roof all around in circumferentially spaced apart relation thereby to permit the roof substantially to float on the tank between the deflated position and the extended position which is determined by the distance between the lowermost girder 32 and the attachment on the lower end portion of the post 64 and also by the distance which the skirt 62 extends downwardly into the liquid 48 of the launder thereby to permit the roof to rise to accommodate the increased volume of material within the tank without breaking the sealing relation between the skirt and launder so that the vapors which are present in the tank can be conserved and Subsequently condensed during the colder portions of the day or else removed from the tank when needed for use.

It will be understood that various changes may be made within the skill of the art in the means described for guiding the posts during vertical movements of the roof and for supporting the roof upon the basic structure without departing from the spirit of the invention, especially as defined in the following claims.

We claim:

1. In a storage tank for containing vapors and the like, an open top tank shell having a launder with sealing liquid about the upper end portion of the tank shell, a roof mounted for shifting movement in the direction toward and away from the open end of the tank shell between deflated and extended position of adjustment to vary the volumetric capacity of the tank responsive to the amount of vapor and content material therein, a skirt depending from the outer edge portion of the roof into the sealing liquid of the launder to confine the vapors within the roof covered tank shell, a plurality of posts depending from the roof in spaced apart relation about the outer portion of the roof and into the tank shell in closely spaced relation with the walls thereof, and horizontally disposed plate members fixed to the side walls of the tank as girders to reinforce and stifien the tank walls and having openings therein through which the depending posts extend, the improvement which comprises means on said plates adjacent each of said openings for operative engagement with the posts extending therethrough in each of the radial directions and in each of the circumferential directions to resist angular adjustment and circumferential movement of said posts from normally aligned positions, a horizontally disposed flange fixed to the upper end of the tank shell to form an integral part thereof and a horizontally disposed girder plate fixed to the outer end portion of the roof for cooperating with the flange member on the tank shell by engagement therewith to support the roof when in deflated position thereby uniformly to distribute the load existing between the tank shell and roof over substantial areas and properly to align the elements in position of rest.

2. A storage tank as claimed in claim 1 in which the roof girder fixed to the end portion of the roof for support of the skirt and for engagement with the tank shell to support the roof when in deflated position comprises an annular disc shaped member underlying the edge portion of the roof with the edge portion positioned intermediate the lateral edges thereof and a cylindrical ring member extending vertically between the inner end portion of the disc member and the underside of the roof to form one side of a triangular section in which the other two sides comprise the roof posts outwardly thereof and the disc member between the ring and the edge of the roof.

3. A storage tank as claimed in claim 2 in which a horizon ally disposed flange is formed to extend inwardly from the upper edge portion of the tank shell and in which the horizontally disposed disc shaped member operates in combination therewith for operative engagemcnt thereoetween when the roof is in the deflated position substantially to support the roof all around through a substantial area on the walls of the tank shell.

4. A storage tank as claimed in claim 3 in which the posts depend from the disc shaped member in the portion between the ring member forming the inner leg of the triangular roof girder and the portions of the disc member in vertical alignment with the flange at the top of the tank shell to clear the flange in position of use.

5. In a storage tank of the type described, an open top tank shell of cylindrical shape having a launder with sealing liquid about the upper end portion of the tank shell, a bell shaped roof mounted for shifting movement in the direction toward and away from the open end of the tank shell between deflated and extended position of adjustment to vary the volumetric capacity of the tank responsive to the amount of vapors and content material therein, a skirt depending all around from the roof into the sealing liquid of the launder to confine the vapors within the roof covered tank shell, a plurality of posts depending from the outer portions of the roof in circumferentially spaced apart relation into the tank shell and in closely spaced relation with the walls thereof, horizontally disposed girder plates fixed to the side walls of the tank for reinforcement thereof and having openings therein through which the depending posts extend, the improvement which comprises means on said plates adjacent each of said openings for operative engagement with the posts extending therethrough to engage the inner and outer radial walls of the posts and the clockwise and counter-clockwise circumferential walls of the posts to resist angular adjustment and circumferential movement of the posts from normally aligned positions, in which the means operatively engaging the posts comprises rollers arranged as a pair of radial rollers and a pair of circumferential rollers mounted on the girders about each of the openings for engagement of the radial walls and the circumferential walls respectively of the posts extending downwardly through the openings, means mounting the radial pair of rollers for movement in the radial direction toward and away from the walls of the posts and means mounting the rollers of the circumferential pair for movement in the circumferential direction toward and away from the circumferential walls of the posts, and resilient means constantly urging each of the rollers in a direction towards the walls of the posts resiliently to engage the walls of the posts from opposite radial and circumferential directions thereby constantly to urge the posts separately therebetween within the openings.

6. A storage tank as claimed in claim 5 in which the roller member comprises ball bearings mounted for free rotational movement within a housing.

7. A storage tank as claimed in claim 5 in which the roller member comprises cylindrical rollers mounted for rocking movement in the direction toward and away from the walls of the posts.

8. A storage tank as claimed in claim 5 in which the means resiliently engaging the posts extending downwardly through the openings comprises spring means fixed at one end to the girders with the other end extending into the path of the posts extending downwardly through the openings resiliently to engage the adjacent walls of the posts.

9. In a storage tank for containing vapors and the like, an open top tank shell having a launder with sealing liquid about the upper end portion of the tank shell, a roof mounted for shifting movement in the direction toward and away from the open end of the tank shell between deflated and extended position of adjustment to vary the volumetric capacity of the tank responsive to the amount of vapor and content material therein, a skirt depending from the outer edge portion of the roof into the sealing liquid of the launder to confine the vapors within the roof covered tank shell, a plurality of posts depending from the roof in spaced apart relation about the outer portion of the roof and into the tank shell in closely spaced relation with the walls thereof, horizontally disposed plate members fixed to the side walls of the tank as girders to reinforce and stiffen the tank walls and having openings therein through which the depending posts extend, the improvement which comprises means on said plates adjacent each of said openasse ses ings for operative engagement with the postsextending therethrough in each of the radial directions and in each of the circumferential directions to resist angular adjustment and circumferential movement of said posts from normally aligned positions, a horizontally disposed flange fixed to the upper end of the tank shell to form an integral part thereof and a horizontally disposed girder plate fixed to the outer end portion of the roof for cooperating with the flange member on the tank shell by engagement therewith to support the roof when in deflated position thereby uniformly to distribute the load existing between the tank shell and roof over substantial areas and properly to align the elements in position of rest, tracks fixed to the inner walls of the tank shell in radial and vertical alignment with the posts, and means on the lower end of each of the posts operatively received in the aligned tracks for guiding the posts in vertical movement while holding the posts against angular adjustment and circumferential movement within the tank shell.

10. A storage tank as claimed in claim 9 in which the means on the lower end of the posts comprises rollers fixed to the posts and extending radially outwardly therefrom into operative engagement with the track.

11. A storage tank as claimed in claim 10 which includes means constantly urging the rollers outwardly radially from the posts into resilient engagement with the track.

References Cited in the file of this patent UNITED STATES PATENTS 2,280,768 Graver Apr. 21, 1942 2,360,692 Larsen Oct. 17, 1944 2,452,146 Plummer Oct. 26, 1948 2,685,503 Knecht Aug. 3, 1954 FOREIGN PATENTS 482,812 Canada Apr. 29, 1952 

1. IN A STORAGE TANK FOR CONTAINING VAPORS AND THE LIKE, AN OPEN TOP TANK SHELL HAVING A LAUNDER WITH SEALING LIQUID ABOUT THE UPPER END PORTION OF THE TANK SHELL, A ROOF MOUNTED FOR SHIFTING MOVEMENT IN THE DIRECTION TOWARD AND AWAY FROM THE OPEN END OF THE TANK SHELL BETWEEN DEFLATED AND EXTENDED POSITION OF ADJUSTMENT TO VARY THE VOLUMETRIC CAPACITY OF THE TANK RESPONSIVE TO THE AMOUNT OF VAPOR AND CONTENT MATERIAL THEREIN, A SKIRT DEPENDING FROM THE OUTER PORTION OF THE ROOF INTO THE SEALING LIQUID OF THE LAUNDER TO CONFINE THE VAPORS WITHIN THE ROOF COVERED TANK SHELL, A PLURALITY OF POSTS DEPENDING FROM THE ROOF IN SPACED APART RELATION ABOUT THE OUTER PORTION OF THE ROOF AND INOT THE TANK SHELL IN CLOSELY SPACED RELATION WITH THE WALLS THEREOF, AND HORIZONTALLY DISPOSED PLATE MEMBERS FIXED TO THE SIDE WALLS OF THE TANK AS GIRDERS TO REINFORCE AND STIFFEN THE TANK WALLS AND HAVING OPENINGS THEREIN THROUGH WHICH THE DEPEND- 